Re: [PATCH 10/16] ntb: clean up unnecessary MSI/MSI-X capability find

From: Jon Mason
Date: Thu Aug 08 2013 - 12:42:50 EST


On Thu, Aug 08, 2013 at 09:09:34PM +0800, Yijing Wang wrote:
> PCI core will initialize device MSI/MSI-X capability in
> pci_msi_init_pci_dev(). So device driver should use
> pci_dev->msi_cap/msix_cap to determine whether the device
> support MSI/MSI-X instead of using
> pci_find_capability(pci_dev, PCI_CAP_ID_MSI/MSIX).
> Access to PCIe device config space again will consume more time.
>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> Cc: Jon Mason <jon.mason@xxxxxxxxx>

Acked-by: Jon Mason <jon.mason@xxxxxxxxx>

> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
> drivers/ntb/ntb_hw.c | 7 +++----
> 1 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index 2dacd19..090d1b2 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -758,16 +758,15 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> struct pci_dev *pdev = ndev->pdev;
> struct msix_entry *msix;
> int msix_entries;
> - int rc, i, pos;
> + int rc, i;
> u16 val;
>
> - pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
> - if (!pos) {
> + if (!pdev->msix_cap) {
> rc = -EIO;
> goto err;
> }
>
> - rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
> + rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
> if (rc)
> goto err;
>
> --
> 1.7.1
>
>
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